If it is bad authentication (error 32) before it hits the webhook, then you should check to make sure that you have done the following. This information and more is located in our troubleshooting doc:

you are using the proper auth keys that you pulled from the Twitter app that is designated as your AAAPI dev environment. Since this endpoint requires user auth, you will need to use both your consumer keys and access tokens.

you have properly generated the oauth nonce , oauth_signature , and oauth_timestamp for your request.